When Singapore heats up, poorer households use more water, richer ones turn up the air-con: Study

To deal with Singapore’s heat and humidity, Singaporeans whip out umbrellas, turn on the air-con, and take longer and more frequent showers.
Singapore Press Holdings

Sunny Singapore can get a little too hot sometimes. And when it does, citizens seek refuge in air-conditioned rooms and take showers.

A local study has found that when it comes to fighting the heat, lower-income households and higher-income households wield different weapons.

Lower-income households use more water, whereas higher-income households consume more electricity.

In the average household living in a two-room apartment, even a small temperature increase of 1 degree Celsius leads to water use increasing by 9 litres per day.

In contrast, with the same temperature increase, those staying in five- or six-room apartments – including executive flats and condominiums – consume 2 kilowatt hours per day more electricity on average. This amount is equivalent to operating an air-conditioning unit for two more hours each day.

Consuming more water isn’t a heat-relief option for higher-income households, it seems. The study found that water demand remains unchanged among those households.

The study by Associate Professor Alberto Salvo from the Department of Economics at the National University of Singapore tracked the water and electricity bills of about 130,000 households staying in apartments from September 2012 to December 2015.

Difference in air-con penetration and household income

Previous research by the Department of Statistics cited by Prof Salvo found that less than one-fifth (14 per cent) of one- or two-room apartments with a mean annual household income per person of US$9,300 (S$12,745) had air-conditioning.

On the other hand, almost all (99 per cent) condominium apartments with a mean annual household income per person of US$68,900 had air-conditioning.

Showering more often and longer

According to a survey of 300 people conducted to complement Prof Salvo’s study, 39 per cent of respondents said that they shower more often and longer on a very hot day while 36 per cent indicated that they would turn on the air-conditioner.

Prof Salvo is exploring the possibility of applying Singapore’s findings to other urban Asian cities, such as Mumbai and Jakarta, with different climates or levels of economic development.

He said that the study could contribute towards improving demand forecasting for water and electricity in water-stressed cities in tropical Asia, where incomes are rising.

“This can facilitate better design and allocation of water and electricity grids. Air-conditioners powered by electricity generated from burning fossil fuels come at an environmental cost, but one added benefit is that they may reduce a household’s water demand when seeking relief from heat,” he said.